Diethylammonium-2-(2,6-dichloroanilino)phenylacetate

ABSTRACT

Antiinflammatory and/or analgesic pharmaceutical preparations for topical application which contain salts of alkanecarboxylic acids, novel carboxylic acid salts and the production thereof.

This is a continuation of application Ser. No. 885,370 filed on July 14, 1986 now abandoned, which is a divisional of application Ser. No. 765,416 filed on Aug. 14, 1985 now U.S. Pat. No. 4,619,926, which is a divisional of application Ser. No. 517,606 filed on July 27, 1983 now U.S. Pat. No. 4,551,475, which is a divisional of application Ser. No. 236,097 filed on Feb. 20, 1981 now U.S. Pat. No. 4,407,824.

The present invention relates to pharmaceutical preparations for topical application which contain salts of alkanecarboxylic acids, in particular compounds of the formula ##STR1## wherein R₁ is a group of the formula ##STR2## wherein X₁ and X₂ are hydrogen and X₃ is isobutyl, or X₁ and X₃ are hydrogen and X₂ is benzoyl, or X₁ is hydrogen, X₂ is chlorine, and X₃ is 3-pyrrolin-1-yl, or X₁ is hydrogen, X₂ is a group of the formula --CH═CH--C(OCH₃)═CH--X₄, and X₃ together with X₄ are a bond, and R₂ is methyl, or X₂ and X₃ are hydrogen and X₁ is 2,6-dichloroanilino, and R₂ is hydrogen, or R₁ is a group of the formula ##STR3## wherein X₅ is the common bond with the methine group in formula I, X₆ and X₇ are hydrogen, X₈ is p-methylbenzoyl, Y is a nitrogen atom, and X₉ is a methyl group, or X₅ is a methyl group, X₆ is a common bond with the methine group in formula I, X₇ is a group of the formula --CH═C(OCH₃)--CH═CH--X₁₀, X₈ together with X₁₀ are a bond, Y is nitrogen atom and X₉ is p-chlorobenzoyl, or X₅ is a methyl group, X₆ is the common bond with the methine group in formula I, X₇ is a group of the formula --CH═C(F)--CH═CH--X₁₁, X₈ together with X₁₁ are a bond, Y is a carbon atom and X₉ is (p-methanesulfinylphenyl)methylene, and R₂ is hydrogen, and each of R₃, R₄ and R₅ independently is hydrogen, an aliphatic radical, or two of R₃, R₄ and R₅ together are a bivalent aliphatic radical, unsubstituted or substituted or interrupted by aza, oxa or thia, with the proviso that at least one of R₃, R₄ and R₅ is different from hydrogen, optionally in the form of an isomer, together with conventional carriers and/or excipients for topical application, to the use of compounds of the formula I as antiflammatory agents and/or analgesics for topical application, to novel compounds of the formula I and to the production thereof.

Pharmaceutical preparations for topical application are to be understood as meaning in particular those in which the active ingredient is present in a form in which it can be absorbed by the skin, e.g. together with conventional carriers and/or excipients for topical application.

An aliphatic radical R₃, R₄ or R₅ is preferably a lower alkyl radical which is unsubstituted or substituted by amino, a group of the formula ##STR4## or hydroxyl. Examples of such radicals are lower alkyl, amino-lower alkyl, hydroxyl-lower alkyl, or oligo-hydroxy-lower alkyl.

A bivalent aliphatic radical is e.g. 4- to 7-membered lower alkylene, whilst a bivalent aliphatic radical which is interrupted by optionally substituted aza, or by oxa or thia, is e.g. 4- to 7-membered 3-aza-, 3-oxa- or 3-thia-lower alkylene, in which aza can be substituted e.g. by lower alkyl.

Throughout this specification, the term "lower" employed to qualify organic radicals and compounds denotes preferably those containing up to and including 7, most preferably up to and including 4, carbon atoms.

The general definitions employed within the scope of this specification have the following preferred meanings:

Lower alkyl is e.g. methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl or tert-butyl, and also comprises corresponding pentyl, hexyl or hepty radicals.

Amino-lower alkyl is preferably aminomethyl, 2-aminoethyl, 3-aminopropyl or 4-aminobutyl.

Hydroxy-lower alkyl contains in particular a hydroxyl group and is e.g. hydroxymethyl, 2-hydroxymethyl, 2- or 3-hydroxypropyl or 2-, 3- or 4-hydroxybutyl.

Oligo-hydroxy-lower alkyl contains at least two hydroxyl groups and is e.g. 1,2-dihydroxyethyl, 2,3-di- or 1,2,3-trihydroxypropyl, 2,3,4-trihydroxybutyl, 2,3,4,5-tetrahydroxypentyl or, in particular, 2,3,4,5,6-pentahydroxyhexyl derived from D-glucamine, and also di(hydroxymethyl)methyl, tri(hydroxymethyl)methyl or 2-(dihydroxymethyl)ethyl.

Lower alkylene having 4 to 7 members is preferably 1,4-butylene, 1,5-pentylene, 1,6-hexylene, and 1,7-heptylene.

3-Aza-, 3-oxa- or 3-thia-lower alkylene having 4 to 7 members is preferably 3-aza-, 3-N-lower alkyl-aza-, such as 3-N-methyl-aza-, and 3-oxa- or 3-thia-1,5-pentylene, as well as corresponding butylene, hexylene or heptylene.

The compounds of the formula ##STR5## or the salts thereof, are known. These compounds and their salts with bases are used, for example, as non-steroidal antiinflammatory agents for treating inflammatory conditions. The preperations containing these compounds are administered for the most part orally and also enterally or parenterally, but in this mode of administration side-effects are observed, especially of a gastro-intestinal nature, for example ulceration of the mucosae of the gastro-intestinal tract. The object of treating different forms of inflammatory diseases, especially of rheumatism of soft tissues, consists in avoiding the side-effects which are primarily connected with systemic therapy. This object is preferably attained by topical therapy if penetration of the active ingredient into the site of the inflammation can be successfully ensured. Successful therapy by percutaneous administration, however, frequently fails when using compounds of the formula (IIIa), because penetration of a therapeutically effective amount of active ingredient through the skin into the affected tissue cannot be adequately ensured.

The present invention is based on the surprising observation that the compounds of the formula (I) possess excellent percutaneous penetration and absorption properties.

In addition, the compounds of the formula I have marked anti-inflammatory and analgesic properties. The anti-inflammatory activity can be demonstrated e.g. by the marked reduction in the swelling in rats' paws in the kaolin edema test in accordance with Helv. Physiol. Acta 25, 156 (1967), by rubbing e.g. a gel containing about 0.5 to 5% of active ingredient into the backs of test animals from which the hair has been removed (see Arzneimittel-Forschung 27 (I), 1326 1977). Further, the anti-inflammatory activity of the active ingredient, e.g. in the form of a gel having a concentration of about 0.5 to 5%, when applied topically, can be deduced from the inhibition of abscess formation induced by subcutaneous injection of carageen in rats (see Arzneimittel-Forschung 27 (I), 1326, 1977).

Assays using compounds of the formula I in the phenyl-p-benzoquinone writhing test (J. Pharmacol. Therap. 125, 237, 1959) in the dosage range from about 1.0 to 120 mg p.o. indicate a marked analgesic activity.

Accordingly, the compounds of the formula I are most suitable anti-inflammatory agents for percutaneous application and can also be used as analgesics.

Accordingly, the invention relates to pharmaceutical preparations for topical application which contain a compound of the formula 1, wherein R₁ and R₂ are as defined hereinbefore, each of R₃, R₄ and R₅ independently is hydrogen, a lower alkyl radical which is unsubstituted or substituted by amino, a group of the formula ##STR6## or hydroxyl, or two of R₃, R₄ and R₅ are 4- to 7-membered lower alkylene or 4- to 7-membered lower alkylene which is interrupted by optionally lower alkyl-substituted aza, or by oxa or thia, with the proviso that at least one of R₃, R₄ and R₅ is different from hydrogen, and to the use of these compounds as anti-inflammatory agents and/or analgesics for topical application.

These preparations comprise e.g. pharmaceutical preparations for topical application which contain a compound of the formula I, wherein R₁ and R₂ have the given meanings, each of R₃, R₄ and R₅ independently is hydrogen, lower alkyl, amino-lower alkyl, lower alkyl substituted by a group of the formula ##STR7## hydroxy-lower alkyl, oligo-hydroxy-lower alkyl, or two of R₃, R₄ and R₅ are 4- to 7-membered lower alkylene or 4- to 7-membered lower alkylene which is interrupted by optically N-lower alkylated aza, or by oxa or thia.

The invention relates especially to pharmaceutical preparations for topical application which contain a compound of the formula I, wherein R₁ and R₂ have the given meanings, each of R₃, R₄ and R₅ independently is lower alkyl containing up to and including 4 carbon atoms, such as methyl or ethyl, or hydroxy-lower alkyl containing up to and including 4 carbon atoms, such as 2-hydroxyethyl, or one of R₃, R₄ and R₅ is hydrogen and each of the others independently is lower alkyl containing up to and including 4 carbon atoms, such as ethyl, hydroxy-lower alkyl containing up to and including 4 carbon atoms, such as 2-hydroxyethyl or 2-hydroxypropyl, or together are 4- to 7-membered lower alkylene such as 1,4-butylene or 1,5-pentylene, 4- to 7-membered, optionally N-lower alkylated aza-lower alkylene, or oxa- or thia-lower alkylene, such as 3-aza-, 3-oxa- or 3-thia-1,5-pentylene, or one of the others is lower alkyl containing up to and including 4 carbon atoms, such as methyl, and the third is oligo-hydroxy-lower alkyl such as 2,3,4,5,6-pentahydroxy-1-hexyl which is derived from D-glucamine, or two of R₃, R₄ and R₅ are hydrogen and the other is lower alkyl containing up to and including 4 carbon atoms, such as ethyl, hydroxy-lower alkyl containing up to and including 4 carbon atoms, such as 2-hydroxyethyl, oligo-hydroxy-lower alkyl containing up to and including 4 carbon atoms, such as tris(hydroxymethyl)methyl, amino-lower alkyl containing up to and including 4 carbon atoms, such as 2-aminoethyl, or a group of the formula ##STR8## wherein alk is lower alkylene containing up to and including 4 carbon atoms, such as ethylene, and to the use of these compounds as anti-inflammatory agents and/or analgesics for topical application.

The invention relates more especially to pharmaceutical preparations for topical application which contain a compound of the formula I, wherein R₁ is a group of the formula IIa, in which X₁ is hydrogen, X₂ is a group of the formula --CH═CH--C(OCH₃)═CH--X₄, and X₃ together with X₄ are a bond, and R₂ is methyl, or R₁ is a group of the formula IIa, in which X₁ is 2,5-dichloroanilino, X₂ and X₃ are hydrogen, and R₂ is hydrogen, or R₁ is a group of the formula IIb, in which X₅ is a methyl group, X₆ is the common bond with the methine group of the formula I, X₇ is a group of the formula --CH═C(OCH₃)--CH═CH--X₁₀, X₈ together with X₁₀ are a bond, Y is a nitrogen atom and X₉ is p-chlorobenzoyl and R₂ is hydrogen and R₃, R₄ and R₅ are as just defined above, and to the use of these compounds as anti-inflammatory agents and/or analgesics for topical application.

The invention relates most particularly to pharmaceutical preparations for topical application which contain a compound of the formula I, wherein R₁ and R₂ have the meanings just given above and R₃, R₄ and R₅ are hydroxy-lower alkyl containing up to and including 4 carbon atoms, such as 2-hydroxyethyl, or one of R₃, R₄ and R₅ is hydrogen and the others are lower alkyl containing up to and including 4 carbon atoms, such as ethyl, hydroxy-lower alkyl containing up to and including 4 carbon atoms, such as 2-hydroxyethyl, or 4- to 7-membered oxa-lower alkylene such as 3-oxa-1,5-pentylene, and to the use of these compounds as anti-inflammatory agents and/or analgesics for topical application.

The invention preferably relates to pharmaceutical preparations for topical application which contain a compound of the formula I, in which R₁ is a group of the formula IIa, in which X₁ is 2,6-dichloroanilino and X₂ and X₃ are hydrogen, and R₂ is hydrogen, and R₃, R₄ and R₅ are as defined above, and to the use of these compounds as anti-inflammatory agents and/or analgesics for topical application.

Most preferably, the invention relates to pharmaceutical preparations for topical application which contain a compound of the formula I, wherein R₁ and R₂ are as defined above and one of R₃, R₄ and R₅ is hydrogen and the others are lower alkyl containing up to and including 4 carbon atoms, such as ethyl, or 4- to 7-membered 3-oxa-lower alkylene such as 3-oxa-1,5-pentylene, and to the use of these compounds as anti-inflammatory agents and/or analgesics for topical application.

The invention relates specifically to the pharmaceutical preparations for topical application referred to in the Examples and to the use of these compounds as anti-inflammatory agents and/or analgesics for topical application.

The invention also relates to a process for the production of pharmaceutical preparations for topical application. The process comprises mixing a compound of the formula I with conventional carriers and/or excipients for topical application.

The invention also relates to novel compounds of the formula I, wherein R₁ is a group of the formula IIa, in which X₁ is hydrogen, X₂ is a group of the formula --CH═CH--C(OCH₃)═CH--X₄, and X₃ together with X₄ are a bond, R₂ is methyl and R₃, R₄ and R₅ are ethyl or 2-hydroxyethyl, or one of R₃, R₄ and R₅ is hydrogen and the others are ethyl, 2-hydroxyethyl or 3-oxa-1,5-pentylene, or R₁ is a group of the formula IIa, in which X₁ is 2,6-dichloroanilino, X₂ and X₃ are hydrogen, R₂ is hydrogen, and one of R₃, R₄ and R₅ is hydrogen and the others are ethyl, or each of R₃, R₄ and R₅ is hydroxyethyl, or R₁ is a group of the formula IIb, in which X₅ is methyl, X.sub. 6 is a common bond with the methine group of the formula I, X₇ is a group of the formula --CH═C(OCH₃)--CH═CH--X₁₀, X₈ together with X₁₀ are a bond, Y is a nitrogen atom and X₉ is p-chlorobenzoyl, R₂ is hydrogen, and R₃, R₄ and R₅ are hydroxy-lower alkyl containing up to and including 4 carbon atoms, such as 2-hydroxymethyl, or ethyl, or two of R₃, R₄ and R₅ are hydroxy-lower alkyl containing up to and including 4 carbon atoms, such as 2-hydroxyethyl, or ethyl, and the other is hydrogen, or one of R₃, R₄ and R₅ is hydroxy-lower alkyl containing up to and including 4 carbon atoms, or ethyl, and the others are hydrogen, or an isomer thereof, and to the use thereof, to pharmaceutical preparations containing these compounds, and to a process for their production.

The invention further relates to those novel compounds of the formula I, wherein R₁ is a group of the formula IIa, wherein X₁ is hydrogen, X₂ is a group of the formula --CH═CH--C(OCH₃)═CH--X₄, and X₃ together with X₄ are a bond, R₂ is methyl and R₃, R₄ and R₅ are ethyl or 2-hydroxyethyl, or one of R₃, R₄ and R₅ is hydrogen and the others are ethyl, 2-hydroxyethyl or 3-oxa-1,5-pentylene.

The invention further particularly relates to those novel compounds of the formula I, wherein R₁ is a group of the formula IIa, in which X₁ is 2,6-dichloroanilino, X₂ and X₃ are hydrogen, R₂ is hydrogen, and one of R₃, R₄ and R₅ is hydrogen and the others are ethyl, or R₃, R₄ and R₅ are 2-hydroxyethyl.

The invention relates most particularly to those compounds of the formula I, wherein R₁ is a group of the formula IIb, in which X₅ is methyl, X₆ is a common bond with methine group of the formula I, X₇ is a group of the formula --CH═C(OCH₃)--CH═CH--X₁₀, X₈ together with X₁₀ are a bond, Y is a nitrogen atom, X₉ is p-chlorobenzoyl, R₂ is hydrogen and R₃, R₄ and R₅ are hydroxy-lower alkyl containing up to and including 4 carbon atoms, such as 2-hydroxyethyl, or ethyl, or two of R₃, R₄ and R₅ are hydroxy-lower alkyl containg up to and including 4 carbon atoms, such as 2-hydroxyethyl, or ethyl, and the other is hydrogen, or one of R₃, R₄ and R₅ is hydroxy-lower alkyl containing up to and including 4 carbon atoms, PG,11 such as 2-hydroxyethyl, or ethyl, and the others are hydrogen,

The invention relates specifically to the novel compounds obtained in the Examples and to the methods of preparing them described therein.

Depending on the choice of starting materials and procedures, the compounds of the formula I can be obtained in the form of a possible isomer or of a mixture of isomers, for example optical isomers such as enantiomers or diastereomers, or geometrical isomers such as cis-trans-isomers. The optical isomers are in the form of the pure antipodes and/or racemates. Resultant racemates or mixtures of geometrical isomers can be separated into the pure constituents on the basis of the chemico-physical differences between the components. Thus, for example, racemates of optical antipodes can be resolved into the corresponding antimers by methods which are known per se, e.g. by chromatographic methods, by fractional crystallisation, with micro-organisms or enzymes. Further, it is possible to enrich e.g. optical antipodes by conversion of the other antimer in a racemic mixture. The isomers of novel compounds of the formula I also constitute an object of the invention.

The invention also relates to the production of novel compounds of the formula I, which are obtained by methods which are known per se.

A preferred process variant comprises e.g. reacting an organic carboxylic acid of the formula ##STR9## or a base salt thereof which is different from a salt of the formula I, with an at least equimolar amount of the amine of the formula ##STR10## or an acid addition salt thereof, and, if desired, converting a resultant compound of the formula I into another compound of the formula I and/or resolving a resultant mixture of isomers into its individual components.

The molar ratio of acid of the formula (IIIa) and amine of the formula (IIIb) depends on the choice of desired salt or on the number of substituted amino groups in the corresponding compound of the formula (IIIb).

As acid addition salts of amines of the formula (IIIb) there are used e.g. corresponding hydrohalides, such as hydrochlorides,

The reaction of a compound of the formula (IIIa) with a compound of the formula (IIIb) is preferably conducted in an inert solvent or diluent, if necessary with cooling and heating, e.g. in a temperature range from about 0° to 100° C., preferably at room temperature, in a closed vessel and/or in an inert gas atmosphere, e.g. nitrogen.

Examples of suitable solvents and diluents are: water, alcohols such as lower alkanols, e.g. methanol or ethanol, ethers such as di-lower alkyl ethers, e.g. diethyl ether, cyclic ethers such as dioxane or tetrahydrofurane, ketones such as di-lower alkyl ketones, e.g. acetone, carboxylic acid esters such as lower alkanecarboxylic acid esters, e.g. ethyl acetate, amides such as N,N-di-lower alkylamides, e.g. N,N-dimethyl formamide, sulfoxides such as di-lower alkyl sulfoxides, e.g. dimethyl sulfoxide, or mixtures thereof.

The starting materials for the formulae (IIIa) and (IIIb) are known.

The invention also relates to those embodiments of the process in which the starting materials are prepared in situ, or in which a starting material is obtained from a derivative under the reaction conditions and/or is used in the form of a mixture of isomers or of a pure isomer.

The starting materials of the formula (IIIa) can be formed e.g. under the reaction condition from corresponding esters, such as lower alkyl esters, by hydrolysis in the presence of a base, such as an amine, e.g. dimethylamine. An amine of the formula (IIIb) can be used e.g. in the form of an acid addition salt, such as a halide, e.g. a hydrochloride, and liberated in the presence of a base, such as an amine.

In the process of this invention it is preferred to us those starting materials which lead to particularly useful compounds.

The pharmaceutical preparations of this invention for topical application contain the compounds of the formula I together with a pharmaceutically acceptable carrier or excipient. The daily dosage of the active ingredient depends on the age and individual condition of the patient and also on the mode of application.

Suitable pharmaceutical preparations for topical application are primarily creams, ointments and gels, as well as pastes, foams, tinctures and solutions, which contain from about 0.5 to about 5% of active ingredient.

Creams or locations are oil-in-water emulsions which contain more than 50% of water. Fatty alcohols are chiefly used as oleaginous base, for example lauryl, cetyl or stearyl alcohol, fatty acids, for example palmitic or stearic acid, liquid to solid waxes, for example isopropyl myristate, wool wax or bees-wax, and/or hydrocarbons, for example petroleum jelly (petrolatum) or paraffin oil. Suitable emulsifiers are surface-active substances with primarily hydrophilic properties, such as corresponding non-ionic emulsifiers, for example fatty acid esters of polyalcohols or ethylene oxide adducts thereof, such as polyglycerol fatty acid esters or polyoxyethylene sorbitan fatty acid esters (Tweens); polyoxyethylene fatty alcohol ethers or esters; or corresponding ionic emulsifiers, such as alkali metal salts of fatty alcohol sulfates, for example sodium lauryl sulfate, sodium cetyl sulfate or sodium stearyl sulfate, which are customarily used in the presence of fatty alcohols, for example cetyl alcohol or stearyl alcohol. Additives to the aqueous phase include agents which reduce water loss through evaporation, for example polyalcohols, such as glycerol, sorbitol, propylene glycol and/or polyethylene glycols, as well as preservatives, perfumes etc.

Ointments or lotions are water-in-oil emulsions which contain up to 70%, preferably however about 20% to 50%, of water or aqueous phase. The oleaginous phase comprises mainly hydrocarbons, for example petroleum jelly, paraffin oil and/or hard paraffins, which preferably contain hydroxy compounds suitable for improving the water-adsorption, such as fatty alcohols or esters thereof, for example cetyl alcohol or wool wax alcohols, or wool wax. Emulsifiers are corresponding lipophilic substances, such as sorbitan fatty acid esters (Spans), for example sorbitan oleate and/or sorbitan isostearate. Additives to the aqueous phase include humectants, such as polyalcohols, for example glycerol, propylene glycol, sorbitol and/or polyethylene glycol, and preservatives, perfumes etc.

Microemulsions are isotropic systems based on the following four components: water, an emulsifier such as a surfactant, e.g. Eumulgin®, a lipid such as a non-polar oil, e.g. paraffin oil, and an alcohol containing a lipophilic group, e.g. 2-octyldodecanol. If desired, other ingredients can be added to the microemulsions.

Greasy ointments are anhydrous and contain as base in particular hydrocarbons, for example paraffin, petroleum jelly and/or liquid paraffins, and also natural or partially synthetic fat, for example coconut fatty acid triglycerides, or preferably hardened oils, for example hydrated ground nut or castor oil, and also fatty acid partial esters of glycerol, for example glycerol mono- and distearate, and, for example, the fatty alcohols, emulsifiers and/or additives for increasing the water-adsorption mentioned in connection with the ointments.

In the case of gels a distinction is made between aqueous gels, anhydrous gels, and gels having a low water content, and which consists of swellable gel-forming materials. Primarily transparent hydrogels based on inorganic or organic macromolecules are used. High molecular inorganic components with gel-forming properties are chiefly water-containing silicates such as aluminium silicates, e.g. bentonite, magnesium aluminium silicates, e.g. veegum, or colloidal silica, e.g. aerosil. As high molecular organic substances there are used e.g. natural, semi-synthetic or synthetic macromolecules. Natural and semi-synthetic polymers are derived e.g. from polysaccharides with carbohydrate compounds of the most widely different kind, such as celluloses, starches, tragacanth, gum arabic, agar-agar, gelatin, alginic acid and salts thereof, e.g. sodium alginate, and their derivatives such as lower alkyl celluloses, e.g. methyl or ethyl cellulose, carboxy- or hydroxy-lower alkyl cellulose, e.g. carboxymethyl cellulose or hydroxyethyl cellulose. The components of synthetic gel-forming macromolecules are e.g. correspondingly substituted unsaturated aliphatics such as vinyl alcohol, vinyl pyrrolidine, acrylic or methacrylic acid. Examples of such polymers are polyvinyl alcohol derivatives such as polyviol, polyvinyl pyrrolidines such as collidone, polyacrylates and polymethacrylates such as Rohagit S® or Eudispert®. Conventional additives such as preservatives or perfumes can be added to the gels.

Pastes are creams and ointments containing powdered ingredients which absorb secretions, such as metal oxides, for example titanium oxide or zinc oxide, and talc and/or aluminium silicates whose purpose it is to bind moisture or secretion present.

Foams are administered from pressurised dispensers and are liquid oil-in-water emulsions in aerosol form, with halogenated hydrocarbons, such as chlorofluoro-lower alkanes, for example dichlorodifluoromethane and dichlorotetrafluoroethane, being used as propellants. For the oleaginous phase there are used, inter alia, hydrocarbons, for example paraffin oil, fatty alcohols, for example cetyl alcohol, fatty acid esters, for example isopropyl myristate, and/or other waxes. As emulsifiers there are used, inter alia, mixtures of those emulsifiers with primarily hydrophilic properties, such as polyoxyethylene sorbitan fatty acid esters (Tweens), and those with primarily lipophilic properties, such as sorbitan fatty acid esters (Spans). In addition, the conventional additives are used, such as preservatives etc.

Tinctures and solutions generally have an aqueous ethanolic base to which are added, inter alia, polyalcohols, for example glycerol, glycols, and/or polyethylene glycol, as humectants for reducing water loss, and fat-restorative substances, e.g. fatty acid esters with lower polyethylene glycols, i.e. lipophilic substances which are soluble in the aqueous mixture as substitute for fatty substances which are removed from the skin by the ethanol, and, if necessary, other assistants and additives.

The pharmaceutical preparations for topical application are obtained in known manner, for example by dissolving or suspending the active ingredient in the base or in a part thereof, if necessary. When processing the active ingredient in the form of a solution, it is usually dissolved in one of the two phases before the emulsification, and when processing the active ingredient in the form of a suspension, it is mixed with a part of the base before the emulsification and than added to the remainder of the formulation.

The invention also relates to the use of the novel compounds of the formula I as anti-inflammatory agents for percutaneous application and/or as analgesics, preferably in the form of suitable pharmaceutical preparations.

The following Examples illustrate the invention but in no way limit the scope thereof.

EXAMPLE 1

To a solution of 2 g of 2-(2,6-dichloroanilino)phenylacetic acid in 40 ml of ether are added 2 ml of diethylamine. The solution is refluxed for 10 minutes, then cooled and concentrated under reduced pressure, whereupon diethylammonium-2-(2,6-dichloroanilino)phenylacetate crystallises out. The colourless crystals are isolated by filtration (m.p. 110°-115° C. with decompos.) and dried at room temperature in a high vacuum. ##STR11## The following compounds are obtained in analogous manner: diethylammonium-[2-(6-methoxy-2-naphthyl)]-propionate with a melting point of 72°-83° C. (decompos.), starting from diethylamine and 2-(6-methoxy-2-naphthyl)propionic acid; diethylammonium-[1-(p-chlorobenzoyl)-5-methoxy-2-methyl-3-indolyl]-acetate with a melting point of 98°-125° C. (decompos.), starting from diethylamine and [1-(p-chlorobenzoyl)-5-methoxy-2-methyl-3-indolyl]-acetic acid.

EXAMPLE 2

With efficient stirring, a solution of 4.53 g of tris-(hydroxymethyl)methylamine in 10 ml of water is added dropwise at room temperature and in the course of 10 minutes to a solution of 10 g of 2-(2,6-dichloroanilino)phenylacetic acid in 230 ml of ethyl acetate, whereupon a salt immediately precipitates. The batch is subsequently stirred for half an hour at room temperature and the solvent is removed by rotary evaporation. The white crystalline residue is dissolved in 1 liter of acetone/water (1:1) at about 50° C. The hot solution is concentrated in a rotary evaporator until the first crystals precipitate. The residue is left to crystallise at 0° C., and the precipitated white flocculent crystals are collected on a suction filter and dried in a high vacuum. The resultant tris-(hydroxymethyl)methylammonium-2-(2,6-dichloroanilino)phenylacetate has a melting point of 202°-204° C.

EXAMPLE 3

With efficient stirring, a solution of 5.52 g of triethanolamine in 30 ml of ethyl acetate is added dropwise at room temperature and in the course of 10 minutes to a solution of 10 g of 2-(2,6-dichloroanilino)phenylacetic acid in 230 ml or ethyl acetate, whereupon a salt precipitates immediately. The batch is subsequently stirred for about half an hour at room temperature and the solvent is removed in a rotary evaporator. The white crystalline residue is dissolved in a small amount of hot ethanol and crystallised at 0° C. The white crystals are filtered with suction and dried in a high vacuum. The so obtained triethanolammonium-2-(2,6-dichloroanilino)phenylacetate metls at 137°-138° C.

EXAMPLE 4

With efficient stirring, a suspension of 3.89 g of diethanolamine in 30 ml of ethyl acetate is added dropwise at room temperature and in the course of 10 minutes to a solution of 10 g of 2-(2,6-dichloroanilino)phenylacetic acid in 230 ml of ethyl acetate, whereupon a salt precipitates immediately. The batch is subsequently stirred for half an hour at room temperature and the solvent is removed in a rotary evaporator. The yellowish crystalline residue is dissolved in a small amount of boiling ethanol. The solution is left to stand at 0° C. and diethanolammonium-2-(2,-dichloroanilino)-phenylacetate with a melting point of 130°-132° C. crystallises out.

EXAMPLE 5

With efficient stirring, 3.22 g of morpholine in 30 ml of ethyl acetate are added dropwise at room temperature and in the course of 10 minutes to a solution of 10 g of 2-(2,6-dichloroanilino)phenylacetic acid in 230 ml of ethyl acetate. A salt precipitates about 10 minutes after addition of the morpholine. The batch is then stirred for 1 hour at room temperature and the solvent is removed by rotary evaporation. The white crystalline precipitate is dissolved in boiling ethanol. Morpholinium-2-(2,6-dichloroanilino)-phenylacetate with a melting point of 162°-165° C. crystallises out at 0° C.

The following compounds are obtained in analogous manner: morpholinium-[2-(6-methoxy-2-naphthyl)]-propionate, starting from morpholine and 2-(6-methoxy-2-naphthyl)propionic acid; morpholinium[1-(p-chlorobenzoyl)-5-methoxy-2-methyl-3-indolyl]-acetate, starting from morpholine and [1-(p-chlorobenzoyl)-5-methoxy-2-methyl-3-indolyl]acetic acid.

EXAMPLE 6

With efficient stirring, 4.93 g of diisopropanolamine in 30 ml of ethyl acetate are added dropwise at room temperature and in the course of 5 minutes to a solution of 10 g of 2-(2,6-dichloroanilino)phenylacetic acid in 230 ml of ethyl acetate. A salt precipitates after a short time. The batch is stirred for 1 hour and the solvent is removed by rotary evaporation. The white crystalline precipitate is dissolved in a small amount of hot ethanol and the solution is left to stand at 0° C., whereupon diisopropanolammonium-2-(2,6-dichloroanilino)phenylacetate with a melting point of 165°-170° C. crystallises out.

EXAMPLE 7

A suspension of 6.64 g of N-methyl-D-glucamine in 100 ml of ethanol together with 10 g of 2-(2,6-dichloroanilino)phenylacetic acid in 230 ml of ethyl acetate are stirred at room temperature overnight under nitrogen. Fine, white crystals precipitate after 2 hours. The solvent is then removed by rotary evaporation and the white tacky residue is dissolved in a small amount of hot water. The clear solution is slowly cooled to 0° C. and left to stand overnight at 0° C. The oily, semi-crystalline precipitate obtained is collected over 2 days on a celite and cloth filter. The filter cake is dried for a week at 60° C./100 mm Hg and then pulverised. The so obtained N-methyl-D-glucammonium-2-(2,6-dichloroanilino)-phenylacetate melts at 127°-130° C.

EXAMPLE 8

An ointment containing 5% of diethylammonium-2-(2,6-dichloroanilino)phenylacetate is prepared as follows:

    ______________________________________                                         Composition                                                                    ______________________________________                                         propylene glycol         10-44%                                                high molecular polyalkylene glycol                                                                      10%                                                   viscous paraffin oil     12%                                                   white vaseline           22%                                                   microcrystalline wax     7%                                                    glycerol                 0-34%                                                 parabenes                0.2%                                                  active ingredient        5%                                                    ______________________________________                                    

The active ingredient is dissolved in a mixture of glycerol and propylene glycol and the other components are fused together. The active ingredient solution is then emulsified into the oleaginous phase. If desired, perfume (0.1%) is added after the mixture has been stirred cold.

An ointment containing 0.5% or 2% is prepared in similar manner.

EXAMPLE 9

A transparent hydrogel containing 5% of diethylammonium-2-(2,6-dichloroanilino)phenylacetate is prepared as follows:

    ______________________________________                                         Composition                                                                    ______________________________________                                         active ingredient       5%                                                     propylene glycol        10-20%                                                 isopropanol             20%                                                    hydroxypropylmethyl cellulose                                                                          2%                                                     water to make up        100%                                                   ______________________________________                                    

The hydroxypropylmethyl cellulose is swelled in water and the active ingredient is dissolved in a mixture of isopropanol and propylene glycol. The active ingredient solution is then mixed with the cellulose derivative and, if desired, perfume (0.1%) is added. A gel containing 0.5% or 2% of active ingredient is prepared in similar manner.

EXAMPLE 10

A transparent hydrogel containing 5% of diethylammonium 2-(2,6-dichloroanilino)phenylacetate is prepared as follows:

    ______________________________________                                         Composition                                                                    ______________________________________                                         active ingredient      5%                                                      propylene glycol       20%                                                     isopropanol            20%                                                     acrylic acid polymer   2%                                                      triethanolamine        3%                                                      water to make up       100%                                                    ______________________________________                                    

The acrylic acid polymer and water are dispersed and neutralised with triethanolamine. The active ingredient is dissolved in a mixture of isopropanol and propylene glycol. The active ingredient solution is then mixed with the gel. If desired, perfume (0.1%) can be added.

A gel containing 0.5% or 2% of active ingredient can be prepared in similar manner.

EXAMPLE 11

A transparent microemulsion containing 5% of diethylammonium 2-(2,6-dichloroanilino)phenylacetate is prepared as follows:

    ______________________________________                                         Composition                                                                    ______________________________________                                         active ingredient       5%                                                     cetyl stearyl alcohol   27%                                                    polyol fatty acid ester 15%                                                    glycerol                4%                                                     water to make up        100%                                                   ______________________________________                                    

The cetyl stearyl alcohol and polyol fatty acid ester are heated to 95° C. and the active ingredient is dissolved therein. A mixture of water and glycerol, which has been heated to 95° C., is added. If desired, 0.2% of preservative is added. The resultant microemulsion is cooled, with stirring, and perfume (0.1%) is added, if desired. Transparent emulsion containing 0.5% or 2% of active ingredient are prepared in similar manner.

EXAMPLE 12

A lotion containing 5% of diethylammonium-2-(2,6-dichloroanilino)phenylacetate is prepared as follows:

    ______________________________________                                         Composition                                                                    ______________________________________                                         active ingredient          5%                                                  mono- and diglycerides of higher saturated                                                                8%                                                  fatty acids with potassium stearate                                            polyoxyethylene cetyl stearyl ether                                                                       2%                                                  decyl oleate               5%                                                  propylene glycol           20%                                                 parabenes                  0.2%                                                demineralised water to make up                                                                            100%                                                ______________________________________                                    

The active ingredient and the parabens are dissolved in water and propylene glycol. Then polyoxyethylene cetyl stearyl ether is added to the above solution. Decyl oleate and the glycerides of fatty acids with potassium stearate are fused together and emulsified into the aqueous phase. The lotion is stirred cold and, if desired, perfume (0.1%) is added.

EXAMPLE 13

A solution containing 5% of diethylammonium-2-(2,6-dichloroanilino)phenylacetate is prepared as follows:

    ______________________________________                                         Composition                                                                    ______________________________________                                         active ingredient          5%                                                  polyoxyethylene sorbitan fatty acid ester                                                                 10%                                                 ethanol                    20%                                                 triglyceride (liquid)      65%                                                 ______________________________________                                    

The active ingredient is dissolved in ethanol and the polyoxyethylene sorbitan fatty acid ester is dissolved in liquid triglyceride. The two solutions are combined and, if desired, perfume (0.1%) is added.

Solutions containing 0.5% and 2% respectively of active ingredient are prepared in similar manner.

EXAMPLE 14

An ointment containing 5% of diethylammonium-2-(2,6-dichloroanilino)phenylacetate is prepared as follows:

    ______________________________________                                         Composition                                                                    ______________________________________                                         active ingredient          5%                                                  mono- and diglycerides of higher saturated                                                                17%                                                 fatty acids with potassium stearate                                            decyl oleate               5%                                                  propylene glycol           20%                                                 demineralised water to make up                                                                            100%                                                ______________________________________                                    

The active ingredient is dissolved in propylene glycol and water. Mono- and diglycerides of saturated fatty acids with potassium stearate are fused together with decyl oleate. The aqueous phase is then added to the oleaginous phase and emulsified. If desired, perfume (0.1%) is added

A cream containing 0.5% and 2% respectively of active ingredient is prepared in similar manner.

EXAMPLE 15

An ointment containing 5% of diethylammonium 2-(2,6-dichloroanilino)phenylacetate is prepared as follows:

    ______________________________________                                         Composition                                                                    ______________________________________                                         active ingredient        5%                                                    propylene glycol         12%                                                   vaseline, white          28%                                                   wax (microcrystalline)   2%                                                    sorbitan fatty acid ester                                                                               25%                                                   demineralised water to make up                                                                          100%                                                  ______________________________________                                    

The active ingredient is dissolved in propylene glycol and water. The vaseline, wax and sorbitan fatty acid esters are fused together. The active ingredient solution is then emulsified into the oleaginous phase and, if desired, perfume (0.1%) is added.

An ointment containing 0.5% and 2% respectively of active ingredient is prepared in similar manner.

EXAMPLE 16

A lotion contining 2% of diethylammonium 2-(2,6-dichloroanilino)phenylacetate is prepared as follows:

    ______________________________________                                         Composition                                                                    ______________________________________                                         active ingredient         2%                                                   high molecular polyalkylene glycol                                                                       14%                                                  liquid triglyceride       5%                                                   viscous paraffin oil      13%                                                  glycerol sorbitan fatty acid ester                                                                       10%                                                  demineralised water to make up                                                                           100%                                                 ______________________________________                                    

The active ingredient is dissolved in polyalkylene glycol and water. Triglyceride, paraffin oil and glycerol sorbitan fatty acid ester are fused together. The aqueous phase is then emulsified into the oleaginous phase and, if desired, perfume (0.1%) is added. A lotion containing 0.5% of active ingredient is prepared in similar manner.

Ointments, creams, gels, microemulsions, lotions and solutions containing 0.5%, 2% or 5% of the compounds of Examples 1 to 7 are prepared in the same way as in Examples 8 to 16. 

What is claimed is:
 1. A compound being diethylammonium-2-(2,6-dichloroanilino)phenylacetate. 